Special Issue Information

Dear Colleagues,

Since their first scientific report by Gutowski et al. in 2003, ionic-liquid-based aqueous biphasic systems became one of the most promising areas of application of ionic liquids. Prof. João A.P. Coutinho and Prof. Robin D. Rogers join efforts on this special issue to celebrate the first decade of work on this subject. The last decade witnessed the publication of more than 200 articles in the characterization and application of these systems but, in spite of the reported successes in the extraction and purification of a wide range of compounds, in particular biomolecules, it is sure that this field is still on its infancy. The number of potential systems keeps increasing surpassing by far the conventional polymer-salt or polymer-polymer ABS. Many of their characteristics and properties are still unknown. The driving mechanisms responsible for the phase splitting and partitioning behavior on these systems are only partly understood. No attempts at modeling have yet been reported and only lab scale trials were carried out. Besides ABS extractions from aqueous media using immiscible or partially miscible ionic liquids, thermoreversible systems based on UCST and LCST have been reported extending the range of potential application of liquid-liquid extractions from aqueous media. A deeper understanding of the systems' underlying mechanisms, their application to new fields such as in metal recovery, and a whole range of technical issues related with the back extraction and purification of compounds, as well as the recovery of the ionic liquids employed, must be tackled in what seems to be a most exciting next decade of research on IL-based extractions. This is a moment of celebration for all researchers that have been working on this subject and research contributions on the most various issues related with IL-based extractions from aqueous media are welcome.

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. Papers will be published continuously (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are refereed through a peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. International Journal of Molecular Sciences is an international peer-reviewed Open Access monthly journal published by MDPI.

Abstract: We designed phosphonium-type zwitterion (ZI) to control the saturated water content of separated ionic liquid (IL) phase in the hydrophobic IL/water biphasic systems. The saturated water content of separated IL phase, 1-butyl-3-methyimidazolium bis(trifluoromethanesulfonyl)imide, was considerably improved from 0.4 wt% to 62.8 wt% by adding N,N,N-tripentyl-4-sulfonyl-1-butanephosphonium-type ZI (P555C4S). In addition, the maximum water content decreased from 62.8 wt% to 34.1 wt% by increasing KH2PO4/K2HPO4 salt content in upper aqueous phosphate buffer phase. Horse heart cytochromec (cyt.c) was dissolved selectively in IL phase by improving the water content of IL phase, and spectroscopic analysis revealed that the dissolved cyt.c retained its higher ordered structure. Furthermore, cyt. c dissolved in IL phase was re-extracted again from IL phase to aqueous phase by increasing the concentration of inorganic salts of the buffer solution.